The present invention relates to centrifuge apparati and more particularly to a centrifuge which works in conjunction with a cassette, rotor or other device having fluid retentive chambers and fluid flow tubing fixedly attached to the axis of the device.
In the context of mechanisms which have come to be known as continuous flow centrifuges, when a length of tubing is fixedly attached to the rotation axis of a device which contains the fluid material to be centrifuged, the entire length of tubing must be rotated by use of rotary seals or some other means to avoid twisting the tubing. A well known method for avoiding the use of rotary seals is to curve the length of tubing outwardly from the axis and around the outer edge of the circumference of the rotor, cassettes or the like and, to rotate the tubing in an orbital fashion around the rotor/cassette at one-half times the rotational speed of the rotor/cassette itself. Such a method for eliminating tube twisting and apparati therefore are disclosed, for example, in U.S. Pat. Nos. 4,216,770, 4,419,089 and 4,389,206.
Problems inherent in such prior apparatuses which orbit the fluid flow tubing around the axis of centrifuge rotation are that the axis of rotation is disposed vertically, the tubing is routed through an axial shaft and the apparatus is driven by driving an axial shaft which requires a high aspect ratio and an elongated shaft which limit the rotational speed, render the apparatus instable and limits the ability of the user to mount a second cassette, rotor or the like on opposing sides of the chuck component of the apparatus.
In accordance with the foregoing, reference is also made to U.S. Pat. No. 5,665,048 that provides a centrifuge for rotating a fluid retentive housing having fluid input and output tubing fixedly connected to a rotation axis of the fluid retentive housing, the centrifuge comprising: a frame; a first rotatable mechanism having a rotation axis, the fluid retentive housing being coaxially mounted thereon for co-rotation therewith; a second rotatable mechanism having a rotation axis, the first and second rotation mechanism being coaxially mounted on the frame; the second rotatable mechanism having an outer circumferential surface engaged with a drive mechanism, the drive mechanism driving the outer circumferential surface such that the second rotatable mechanism rotates at a selected rotational speed X; the first rotatable mechanism being interconnected to the second rotatable mechanism such that the first rotatable mechanism rotates simultaneously with the second rotatable mechanism at a rotational speed of 2X.
The second rotatable mechanism includes a seat for holding a distal length of the output tubing which extends from the axis of the fluid retentive housing, wherein the distal length of the output tubing held by the seat is rotated around the rotation axis at the same rotational speed as the second rotatable mechanism. One of the problems associated with such an arrangement is that there is continuous friction between the tubing and the seat.